The present invention relates to a vacuum sampling vial and more particularly to a vacuum sampling vial capable of safe sample extraction in only a single step.
With the advance of quantitative laboratory measuring techniques to easily and accurately measure certain ionic species such as heavy metals (i.e., Pb, Fe, Cu) in ultra low ranges (0-25 ppb) the need to obtain water samples which are truly untainted has increased many fold.
To date, water sampling technologies for trace level water samples require a skilled operator to extract a sample because of the handling of hazardous materials used to stabilize water samples and the need to prevent exposure to contaminants introduced from unclean vessels or implements. The risk of sample contamination is so great for extreme low level measurements that sterilized sampling containers once opened to permit the sample to be placed in it can be contaminated by exposure to surrounding environmental conditions. Additionally, once the sample has been extracted and inoculated with a stabilizer such as concentrated nitric acid for copper samples, a product results which has personal and transportation hazards.
For example, to test for the presence of the element copper in water via the use of an ICP (Inductively Coupled Plasma) analyzer, the currently available sampling systems provide for a multi step extraction procedure before the ICP can perform its analysis. Steps involved are the filling of a copper free bottle with water, sample inoculation with copper free nitric acid, extraction of the sample from the sample container via copper free apparatus such as a pipetter and resealing of the sample container without contamination and for eventual environmentally safe disposal of the excess acidified sample. The entire procedure can take hours.
In our patent application Ser. No. 07/781,875 entitled "Vial With Powdered Reagent" filed on Oct. 24, 1991, we describe a method of manufacturing an evacuated vial containing a powdered reagent under conditions in which contamination is avoided so that the vial can be stored for an indefinite period of time. Once the frangible tip is broken and the vial is filled with a sample and taken to a laboratory for analysis. If it were desired to remove the sample, the sample will not leave the vial merely by unsealing the neck due to the narrow diameter of the opening so that destruction of the vial itself is required with the attendant risks of contamination. Hence, so that the use of such an evacuated vial either requires a more expensive procedure to avoid the contamination or the use of such a vial is limited to circumstances where contamination is not considered to be a problem.
In other words, evacuated sampling vials are not useful where high levels of purity and accuracy are required due to the inability to transfer the sample from the vial to the testing apparatus without risk of contamination.
A number of United States Patents teach sampling methods and apparatus for testing purposes.
U.S. Pat. No. 3,332,288 discloses a device for sampling molten metal using an elongated tube which is evacuated and has a weakened portion which breaks when thrust into the metal. The tube is made by glass blowing.
U.S. Pat. No. 3,626,762 shows a method and apparatus for filling a capillary tube with liquid in which a wedge device is employed to break the frangible tip of the tube.
U.S. Pat. No. 4,445,390 discloses a sampling tube and apparatus for use in detecting the presence of hydrogen in a molten specimen. A porous plug is employed within the tube through which the hydrogen passes.
U.S. Pat. No. 4,537,747 teaches a disposable sampling device in which an evacuated vial with a frangible tip is employed. The sample is then shaken out of the vial for testing.
None of the preceding patents teaches the present invention.